HELP!!! Error message in Xilinx ISE 8.2i

below is the error message i got from Xilinx ISE 8.2i, this happens when i tried to implement the design, any idea on how to deal with this?? I can't find out the way to track this error >_<''

ERRORrojectMgmt - TOE: ITclInterp::ExecuteCmd gave Tcl result 'invalid command name "0"'.
Tcl_ErrnoId: unknown error
Tcl_ErrnoMsg: No error
_cmd: ::xilinx:pm::dpm_chTransformExecuteForNgdbuild dpm_ngdbuildRun $piThisInterface
errorInfo: invalid command name "0"
while executing
"$_iDu GetDesignUnitType _iDuType"
(procedure "dpm_flowGetDesignFiles" line 24)
invoked from within
"dpm_flowGetDesignFiles $_IDesign $_DuType _HdlFileList _DesignFileList"
(procedure "::xilinx:pm::dpm_chTransformExecuteForNgdbuild" line 60)
invoked from within
"::xilinx:pm::dpm_chTransformExecuteForNgdbuild dpm_ngdbuildRun $piThisInterface"

that probably won't be much help but, why 8.2, up-to-date version of ISE is 10.1, 8 series was so full of bugs that some people on Xilinx forum made up term TTFF - time to first fatal failure, I belive that error you get is just one more bug in 8.2

Added after 13 minutes:

oh and I found that, it is for ISE 9.2 but is should apply to your case as well http://forums.xilinx.com/xlnx/board/message?board.id=ISE&thread.id=1440

I too use ISE 8.2 and in a while I use to receive such errors. But however when I rerun the implementation by cleaning the files, things worked as well...